1. Field of the Invention
The invention generally relates to an apparatus and method useful for the reduction, stabilization, and fixation of pelvic ring fractures, and more particularly, to a modular pelvic fixation apparatus that includes an elongated rod and a plurality of clamps mounted to an exposed fractured pelvis with bone screws.
2. Description of Related Art
Pelvic fractures, both with and without acetabular disruption, frequently require a procedure called open reduction and internal fixation. In this procedure an incision is made in a patient to expose the pelvic ring, and the pelvic bones are manipulated in order to stabilize the fracture. A metal plate is fastened to the bone with bone screws in order to stabilize and fixate or hold the fracture while healing takes place.
Fracture patterns in the acetabulum and pelvic area are widely varied and are often not uniform because the size and shape of these bones vary significantly from patient to patient. Because of the contours of these variably shaped bones, the metal plates used to stabilize and fixate the fractures must be bent and shaped to fit the bone.
A wide variety of internal bone plates are known in the art for fixation of bone fractures. These bone plates are generally mounted to the bone with some type of bone screw, and the surface of the plate that bears against the bone is generally flat or slightly curved. Some plates are formed as straight elongated plates and others are manufactured with a preformed contour to fit certain bone areas. However, few plates are shaped to fit fractures in the acetabulum area.
The contouring of straight plates must be done with extreme care, as the bending can weaken the plate and increase the risk of plate breakage. If a plate is very flexible, the region of the fracture is not sufficiently stabilized, and bone resorption in the fracture gap results due to movement. On the other hand, if the plate is very stiff, the plate takes up all the loading force. This creates an absence of functional loading on the bone, which may lead to general decay of the bone.
In many plates the screw holes are positioned within the main body of the bone plate, which limits the contouring of the plate. Some plates eliminate this problem by providing an elongated rod with screw tabs positioned along the side of the rod. However, the plates are still quite difficult to bend accurately, and contouring can be a time-consuming process when time is critical. Additionally, with this type of plate, as well as others, once a position is chosen for one of the screws, the place of the other screws is predetermined by the location of the screw holes. Also, once the plate is installed, if its position is found to be undesirable or inadequate reduction is obtained, all the screws must be removed and the holes redrilled to reposition the plate.
Thus it would be advantageous to have an internal pelvic fixation device that is strong enough to fix the fracture, but is easily contoured to the desired shape. It would also be advantageous to have as much freedom as possible in the placement of the fixation screws into the pelvis and to be able to change the position of the fixation device easily if the initial site chosen proves unsuitable or if inadequate reduction is obtained. It would additionally be advantageous to have a pelvic fixation system with a mechanism to address fractures of the acetabulum from the medial side.